Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
An image of a document is generally read by using a scanner. A typical scanner is configured to obtain a high-resolution image without a shadow by evenly irradiating the document with a stable light source and causing a line scanner to scan. On the other hand, by a spread of smart phones having a capturing function, it has been desired to read the image of the document using the smart phone.